Keychat users can choose which relays to use. They can also choose not to use Keychat relays at all.

Relays can charge for stamps, but they can also operate for free, although free relays often have other restrictions, such as proof-of-work requirements for messages and frequency limits.

Relays decide which ecash sats issued by mints can be used as stamps.

If a user uses ecash sats issued by a mint that the relay trusts, the relay receives the ecash sats and forwards the message.

When a relay accumulates a certain amount of ecash sats, the relay requests the mint to convert these ecash sats into Lightning Network sats.

If a user uses ecash sats from a mint that the relay has not previously encountered, the relay first receives the ecash sats and then attempts to convert them into Lightning Network sats.

If the conversion is successful, the new mint can be temporarily considered trustworthy, and the message continues to be forwarded.

If the conversion is not successful, the new mint is added to a blacklist, and the message is not forwarded.